JP2007286942A - Method for generating drawing data and data processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for generating drawing data for drawing a desired figure with a thick line having a predetermined width without generating pixels to be drawn twice, and to provide a data processor. <P>SOLUTION: When drawing data of a circle A having a line thickness n is generated, a drawing coordinate generating program (13A) controls a computing process (S1) for the upper end yA and the lower end yB of the y-coordinates of pixels forming a first circle (21) and processes (S3, S5) for registering x-coordinates of the pixels that locate at the outermost position among the pixels forming the first circle and x-coordinates of the pixels that locate at the innermost position among the pixels forming a second circle (22) into a corresponding horizontal line drawing information buffer (11) for each y-coordinate from the upper end to the lower end. Using two registered x-coordinates as one pair, a pixel drawing program (14A) controls a process (S8) for generating drawing data from the coordinate point data from one coordinate point to the other included in the pair. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and a data processor for generating drawing data stored in a frame buffer for displaying a desired figure, and for example, drawing data of a figure based on a specified line thickness and figure parameters. The present invention relates to a drawing data generation method to be generated and a technique effective when applied to a data processor.

  Two-dimensional graphics drawing techniques include mixed processing such as alpha blending and raster operations. Drawing refers to the coordinate points of a plurality of pixels constituting a desired figure, for example, the center coordinates of the pixels on the space specified by the x coordinate axis and the y coordinate axis, and the attributes of the pixels at the calculated coordinate points. Data, for example, data indicating a specific color or the like is calculated, an access address of the frame buffer is generated based on the coordinate point of the pixel, and data such as color is written therein. Patent Document 1 discloses image information supplied to a bitmap display device, for example, drawing efficiency based on outline font data having a data structure that defines a pattern outline as a set of lines when drawing a pattern in a frame buffer. A drawing system and a drawing method that can improve the above are disclosed.

Japanese Patent No. 2659557

  The present inventor has examined a means for generating graphic drawing data for obtaining an expected drawing result based on the specified line thickness and graphic parameters. In the mixing process, for example, a frame buffer in which data indicating the background color is stored is prepared, the data indicating the color at the coordinate point of the pixel constituting the figure, and the frame buffer background at the access address generated from this coordinate point. The pixel calculation is performed on the data indicating the color of the image, and the calculation result is written back to the frame buffer as the drawing data. This is performed for each pixel constituting the figure. In short, the entire figure is drawn by writing the drawing data of all the pixels back to the frame buffer.

  However, in order to draw a thick line with a specified thickness, not only the drawing data of one pixel located at the center of the thickness, but if the pixel is a rectangle, 4 adjacent to the four sides of this one pixel. The drawing data for one pixel must also be generated. For this reason, when pixel drawing data is generated by the mixing process and a circle is drawn with a bold line, coordinate points that are calculated twice are generated. That is, when a thick line is sequentially drawn on the circumference, at least one of the four adjacent pixels is drawn twice. That is, in the mixing process, when the same coordinate point is calculated, the same coordinate point is referred to by referring to the data that is the result of the previous pixel calculation, that is, the data different from the original background color of the frame buffer. Pixel calculation is performed with data indicating the color at the point, and the calculation result is written back to the frame buffer as drawing data. As a result, the drawing data generated by the second pixel calculation is different in color from the drawing data generated by the first pixel calculation. In short, when a mixed process is performed and a figure is drawn with a designated thick line, it is difficult to obtain an expected drawing result.

  An object of the present invention is to provide a drawing data generation method and a data processor capable of generating drawing data for drawing a desired figure with a designated thick line without generating pixels to be drawn twice. It is in.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  The following is a brief description of an outline of typical inventions disclosed in the present application.

  [1] The drawing data generation method according to the present invention is based on the line thickness (n) and graphic parameters specified in the space specified by the first coordinate axis (x) and the second coordinate axis (y). The drawing data of the figure is generated. The drawing data generation method includes a first process (S1), a second process (S3, S5), a third process (S7), and a fourth process (S8). The first process includes a start point (yA) and an end point (yB) on the first coordinate axis of an area including an outer contour graphic (21) and an inner contour graphic (22) according to the thickness of the line. Is calculated. In the second process, from the start point toward the end point, the outer contour graphic and the inner contour graphic on the second coordinate axis for each first coordinate point (yi) on the first coordinate axis. Two coordinate points are calculated. In the third process, among the second coordinate points calculated for each of the first coordinate points, the outermost outer coordinate point (x1, x2) in the outer contour graphic and the innermost in the inner contour graphic The inner coordinate point (x3, x4) is selected, and the outer coordinate point and the inner coordinate point are rearranged in the descending order. In the fourth process, the outer coordinate point and the inner coordinate point are set as one set ((x1, x3), (x4, x2)) in the rearranged order, and from the outer coordinate point included in the one set Drawing data is generated based on the data of the coordinate point reaching the inner coordinate point.

  From the above, since the outer coordinate point of the outer contour graphic and the inner coordinate point of the inner contour graphic are selected for each first coordinate point from the start point to the end point on the first coordinate axis, the pixels constituting the contour of the graphic The coordinate point data can be obtained for each first coordinate. Here, the coordinate point data includes, for example, the coordinate points of the pixels constituting the graphic and the data indicating the attributes of the pixels at the coordinate points, that is, the data indicating the specific color. Since the graphic is drawn with the specified line thickness, there are also pixels between the outer contour graphic and the inner contour graphic. The coordinate points of the pixels existing between these contour figures are included in the coordinate points from the outer coordinate point to the inner coordinate point in one set in the fourth process. Accordingly, in the fourth process, drawing data is generated for each first coordinate point based on the contour of the figure and the coordinate point data of the pixels constituting the inside. For this reason, when the result of pixel calculation by mixing processing such as alpha blending and raster operation is written back to the frame buffer as drawing data, the coordinate point data of a plurality of pixels having a common first coordinate point is the fourth In the processing, each pixel calculation is performed only once. In other words, a pixel drawn twice is not generated. Then, every time the fourth process is performed, if the value of the first coordinate point is incremented by one, for example, the fourth process is performed on all the first coordinate points from the start point to the end point, and the drawing data of the entire figure Can be generated. Therefore, it is possible to generate drawing data that can draw a desired graphic with a designated thick line without generating a pixel to be drawn twice.

  As one specific form of the present invention, when an end point exists in the graphic, the first end point (23a) included in the outer contour graphic and the second end point (24a) included in the inner contour graphic. 5th process (S13) which calculates the 3rd coordinate point (25) between the straight lines (C) which connect with (C) is further included. In the third process, when there is the third coordinate point having the first coordinate point (yd) common to the first coordinate point of the second coordinate point, the third coordinate point and the outer coordinate point or the The inner coordinate points are rearranged in descending order. In the fourth process, drawing data is generated based on data of coordinate points from the third coordinate point to the outer coordinate point or the inner coordinate point. From the above, in a figure with end points, there may be a case where one set of outer coordinate points and inner coordinate points cannot be obtained between straight lines connecting the first end point and the second end point. In this case, a set of the third coordinate point and the outer coordinate point or the inner coordinate point can be obtained by calculating the third coordinate point. In this way, drawing data can also be generated for the first coordinate point of the straight line based on the coordinate point data. For this reason, when drawing data for drawing a figure having an end point is generated, a pixel to be drawn twice is not generated. In addition, examples of the figure having end points include an arc that is a part of a circle, a hyperbola, and a higher-order curve.

  As a specific form of the present invention, when the graphic is a circle (A), the parameters of the graphic are a center point (O) and a radius (r). The outer contour graphic is a first circle (21) centered on the center point and having a first radius larger than the radius. The inner contour graphic is a second circle (22) having a second radius that is centered on the center point, smaller than the radius, and whose difference from the first radius is the thickness. From the above, the start point on the first coordinate axis is, for example, the upper end of a circle, and the end point is the lower end of the circle. At the first coordinate points near the upper end and the lower end of the circle, the second coordinate point of the second circle may not exist. In this case, drawing data at the first coordinate point is generated based on the data of the coordinate point from one outer coordinate point of the first circle to the other outer coordinate point. In addition, at the first coordinate point other than the vicinity of the upper end and the lower end of the circle, drawing data at the first coordinate point is generated based on the data of the coordinate point from the outer coordinate point to the inner coordinate point on the two concentric circles. become. Thereby, it is possible to generate drawing data for drawing a circle with a designated thick line without generating a pixel to be drawn twice. Also, since a circle is drawn with pixels, it is different from a mathematically true circle. However, for example, if the size of the pixels constituting the circle is small and the number of pixels is sufficiently large, it can be recognized as a circle on a liquid crystal bitmap display, for example.

  As one specific form of the present invention, when the radius is r and the thickness is n, if n is an odd number, the first radius is an integer part of a value represented by r + n / 2. And the second radius is an integer part of a value represented by rn / 2. If n is an even number, the first radius is a value indicated by r + n / 2-1 and the second radius is a value indicated by rn / 2. From the above, in order to draw a circle which is a collection of pixels, both the radius and the thickness need to be integers. For this reason, the first radius and the second radius are values obtained by the above formula, and based on the coordinate point data from the outer coordinate point of the first circle to the inner coordinate point of the second circle, Drawing data for drawing a circle having a radius r and a thickness n can be generated.

  [2] A data processor according to the present invention includes a central processing unit (2) and a program memory (10) for storing a program executed by the central processing unit. The program memory generates a drawing data generation program (13A, 14A) for generating drawing data of the graphic based on the line thickness and graphic parameters specified in the space specified by the first coordinate axis and the second coordinate axis. ). The drawing data generation program controls a first process, a second process, a third process, and a fourth process. The first process calculates a start point and an end point on the first coordinate axis of an area including an outer contour graphic and an inner contour graphic according to the thickness of the line. The second process includes a second coordinate point on the second coordinate axis of each of the outer contour graphic and the inner contour graphic for each first coordinate point on the first coordinate axis from the start point to the end point. Is calculated. The third process includes, among the second coordinate points calculated for each first coordinate point, the outermost outer coordinate point in the outer contour graphic, and the innermost inner coordinate point in the inner contour graphic. Then, the outer coordinate point and the inner coordinate point are rearranged in the descending order. The fourth process is based on the coordinate point data from the outer coordinate point to the inner coordinate point included in the first set, with the outer coordinate point and the inner coordinate point as one set in the rearranged order. Generate drawing data.

  As described above, the central processing unit can execute the drawing data generation program [1]. As a result, when a desired figure is drawn with the designated thick line, a pixel to be drawn twice is not generated, so that an expected drawing result can be displayed on a liquid crystal bitmap display or the like.

  FIG. 2 shows an example of a data processor according to the embodiment of the present invention. The data processor 1 includes a central processing unit (CPU) 2, a liquid crystal display interface circuit 3 (LCDIF), and a bus state controller (BSC) 4 that performs bus control such as a data bus / address bus. They are connected via an internal bus (IBUS) 5 comprising a bus / address bus. The data processor 1 is connected to a liquid crystal display 7 via an external bus (EXBUS) 6 via a liquid crystal display interface circuit 3. The data processor 1 is connected to the external memory 9 via the bus state controller 4 and the external memory bus (EXMBUS) 8. The external memory 9 includes, for example, a program storage unit 10, a horizontal line drawing information buffer 11, and a frame buffer 12.

  Various programs to be executed by the CPU 2 are stored in the program storage unit 10. Here, as an example, a drawing coordinate generation program 13A and a pixel drawing program 14A are shown. Although the details will be described later, the horizontal line drawing information buffer 11 is a buffer used when the drawing coordinate generation program 13A and the pixel drawing program 14A are executed, and as illustrated in FIG. And coordinate data storage units 16 to 19.

  The CPU 2 executes, for example, the drawing coordinate generation program 13A and the pixel drawing program 14A based on the line thickness and graphic parameters specified by the input device (not shown), thereby storing data indicating the background color, for example. A mixing process is performed using the frame buffer 12 to generate drawing data for this figure. The drawing data is generated by pixel calculation of data indicating the color at the coordinate points of a plurality of pixels constituting the figure and data indicating the background color of the frame buffer 12 at the access address generated from the coordinate points. Is done. For convenience of explanation, the data indicating the color at the coordinate points of all the pixels constituting the figure is, for example, red. Thereby, the data indicating the color at the coordinate point of the pixel can be held in an appropriate register instead of the dedicated frame buffer. The coordinate point of the pixel is, for example, the center coordinate of the pixel on the space specified by the x coordinate axis and the y coordinate axis. The pixel calculation for generating the drawing data includes, for example, a logical calculation by a raster operation and a color calculation using a mixing ratio by alpha blending, and is performed for each pixel. The generated drawing data is written back to the access address of the frame buffer 12. The CPU 2 outputs the drawing data written back to the frame buffer 12 to a display controller (not shown) via the liquid crystal display interface circuit 3 and the external bus 6. The liquid crystal display 7 displays a figure based on the display timing by the display controller.

  FIG. 1 illustrates a flowchart illustrating a drawing data generation method according to the first embodiment of the present invention. The drawing data generation method according to the first embodiment includes, for example, each process controlled by the drawing coordinate generation program 13A and the pixel drawing program 14A. Here, as an example of a desired figure, a case where drawing data of a circle A having a thickness n, a center point O, and a radius r is generated is shown. Since this circle A is an aggregate of pixels, it is not a so-called true circle. However, if the pixel size is small and the resolution of the liquid crystal display 7 is large, it can be recognized as a circle. The pixel shape is a square. The drawing coordinate generation program 13A controls steps S1 to S7, S9, and S10. Further, the pixel drawing program 14A controls Step S8.

  First, the CPU 2 uses an appropriate input device to specify the line thickness n specified on the space specified by the x coordinate axis and the y coordinate axis illustrated in FIG. 4 and the center point O specified as a graphic parameter. Based on the radius r, the upper end yA and the lower end yB of the y coordinate constituting the first circle 21 are calculated (S1). The first circle 21 is an outer contour graphic, and has a first radius centered on the center point O and larger than the radius r. The first radius is an integer part of a value represented by “r + n / 2” if n is an odd number, and a value represented by “r + n / 2−1” if n is an even number. Here, the radius r of the circle A is the distance from the center point O to the point P. The thickness n is composed of a pixel including the point P and an adjacent pixel having a common y coordinate with the pixel. That is, since the thickness n of the circle A is composed of three pixels, if one side of the pixel is “1”, it is “3”. The values of the upper end yA and the lower end yB are values obtained by subtracting or adding from the yO by the radius of the first circle 21 when the coordinates of the center point O are (xO, yO). In short, if yi of the pixels included in the circle A is yi, yA ≦ yi ≦ yB. Then, yA is held in an appropriate register as an initial value of yi, and similarly yB is held as an upper limit value of yi.

  Next, the CPU 2 secures the horizontal line drawing information buffer 11 by an amount corresponding to each horizontal line from the upper end yA to the lower end yB, that is, a line parallel to the x coordinate axis (S2). Here, the number of horizontal line drawing information buffers 11 to be secured is “yB−yA + 1”. Then, the CPU 2 registers the x coordinate of the outermost pixel among the pixels constituting the first circle 21 in yi in the horizontal line drawing information buffer 11 (S3). At this time, the coordinates of the pixels constituting the first circle 21 are calculated using a Mitchener algorithm known as a circle drawing algorithm. In the Mitchener algorithm, the x-coordinate is the same as that of the center point O, the pixel including the upper end yA is set as the start point, and the next pixel to be drawn is calculated mathematically among the pixels whose angles from the center point O are 45 to 90 degrees. An operation for specifying a pixel close to a perfect circle is performed. The pixels at 0 to 45 degrees and 90 to 360 degrees can be calculated by using the symmetry of the circle A. In short, in step S3, yA, which is the initial value of yi, is read from the register, and as shown in FIG. 4, five pixels included in xA between x coordinates x3 to x4 are calculated by the Mitchener algorithm. The x coordinate of the pixel located on the outermost side is x3 and x4 having the largest distance from the x coordinate of the center point O. Therefore, the CPU 2 registers x3 and x4 in the coordinate data storage units 16 and 17 of the horizontal line drawing information buffer 11 corresponding to yA, respectively.

  Next, the CPU 2 registers the number of x-coordinates registered in step S3 in the registration point storage unit 15 of the horizontal line drawing information buffer 11 corresponding to yA (S4). Here, since x3 and x4 are registered in step S3, “2” is registered as the registration score. Then, the CPU 2 determines, based on the center point O and the radius r, the x coordinate of the innermost pixel among the pixels constituting the second circle 22 at yi, that is, the distance from the x coordinate of the center point O. Is registered in the horizontal line drawing information buffer 11 (S5). The second circle 22 is an inner contour graphic and has a second radius smaller than the radius r centered on the center point O. The second radius is the integer part of the value indicated by “rn−2 / 2” if n is an odd number, and the value indicated by “rn−2” if n is an even number. . The coordinates of the pixels constituting the second circle 22 in yi can be calculated by the above-mentioned Mitchener algorithm. In step S5, first, yA is set as an initial value. However, as shown in FIG. 4, there is no pixel constituting the second circle 22 in yA.

  Next, the CPU 2 registers the number of x-coordinates registered in step S5 in the registration point storage unit 15 of the horizontal line drawing information buffer 11 corresponding to yA (S6). However, in step S5 in yA, since the x coordinate is not registered, the number of registered points remains “2”. Then, the CPU 2 rearranges the x coordinates registered in the horizontal line drawing information buffer 11 corresponding to yA in ascending order (S7). This is because the x coordinate is registered in the order of registration in steps S3 and S6, for example, in the coordinate data storage units 16 to 19 of the horizontal line drawing information buffer 11 at yi.

  Then, the CPU 2 executes the pixel drawing program 14A, refers to the x coordinates rearranged in step S7 two by one, and makes one set from one x coordinate included in the one set to the other x coordinate. Based on the data of the coordinate points that arrive, drawing data is generated while performing a mixing process for each coordinate point, and a horizontal line is drawn (S8). Here, the data of the coordinate point includes not only the coordinate point which is the center coordinate of the pixel, for example, but also data indicating the attribute of the pixel at the coordinate point, that is, data indicating a specific color or the like. In step S8, when the y coordinate is yA, drawing data is generated for each coordinate point from x3 to x4, that is, the contour of the circle A in yA and the coordinate points of the pixels constituting the inside. At this time, the result of pixel calculation by the mixing process is written back to the frame buffer 12 as drawing data. The data indicating the colors at the coordinate points of a plurality of pixels from x3 to x4 having yA is once each. Only pixel calculation is performed. In short, when drawing a horizontal line in yA, a pixel drawn twice is not generated.

  Here, a case where the y coordinate is yC will be described. In yC, the x-coordinate registered in the coordinate data storage units 16 and 17 of the horizontal line drawing information buffer 11 corresponding to yC in step S3 is located on the outermost side of the first circle 21 as shown in FIG. x1 and x2. In step S 4, “2” is added to the registered score storage unit 15. In step S <b> 5, x3 and x4 located on the innermost side of the second circle 22 are registered in the coordinate data storage units 18 and 19. Accordingly, “2” is added to the registration score storage unit 15 in step S6, so that the registration score becomes “4”. In step S7, x1, x3, x4, and x2 are stored in ascending order in the coordinate data storage units 16 to 19 in the horizontal line drawing information buffer 11 corresponding to yC. In step S8, x1 and x3 are one set and x4 and x2 are one set in the order in which they are arranged. Based on the coordinate point data from x1 to x3 and the coordinate point data from x4 to x2, respectively. While performing the mixing process for each coordinate point, drawing data is generated and a horizontal line is drawn. At this time, data indicating colors at coordinate points of a plurality of pixels from x1 to x3 and from x4 to x2 having yC is subjected to pixel calculation only once.

  Next, the CPU 2 increments yi by 1 (S9) and determines whether yi is the lower end yB which is the upper limit value (S10). In step S10, if yi is not yB, the process returns to step S3 again, and the processing up to step S10 is repeated. In short, since the horizontal line is drawn in step S8 for all yi from the start point to the end point, the circle A having the specified thickness n and radius r is created without generating pixels to be drawn twice. Drawing data that can be drawn can be generated. Accordingly, since all the pixels constituting the circle A are drawn only once, the color data at the pixel coordinate points is red as described above. For example, if the background color of the frame buffer 12 is blue, All the colors indicated by the drawing data generated by the pixel calculation are purple. Thus, the CPU 2 can display the expected drawing result on the liquid crystal display 7 by executing the drawing coordinate generation program 13A and the pixel drawing program 14A.

  FIG. 5 illustrates a flowchart illustrating a drawing data generation method according to the second embodiment of the present invention. The drawing data generation method according to the second embodiment includes, for example, each process controlled by the drawing coordinate generation program 13B and the pixel drawing program 14B. Here, as an example of a desired figure, a case where drawing data of an arc B that is a part of a circle having a thickness n and a radius r is generated is shown. Since this arc B is a part of a circle, it has end points. The arc B is an outer contour graphic, a pixel constituting the first arc 23 having the end points 23a, 23b, and a pixel constituting the inner contour graphic, the second arc 24 having the end points 24a, 24b. And pixels existing between the first arc 23 and the second arc 24. For example, even if the CPU 2 executes the drawing coordinate generation program 13A and the pixel drawing program 14A according to the first embodiment and tries to draw a horizontal line based on the pixels constituting the arc B having yi for each y coordinate yi. In some cases, only one x coordinate is registered in the horizontal line drawing information buffer 11.

  That is, the pixel 25 included in the straight line C connecting the end point 23a of the first arc 23 and the end point 24a of the second arc 24 illustrated in FIG. It is neither a pixel constituting the pixel nor a pixel constituting the second arc 24. However, the pixel 25 is a pixel constituting the arc B. Here, when the CPU 2 executes the drawing coordinate generation program 13A, only one coordinate point of the pixel located on the outermost side of the first arc 23 is registered in the horizontal line drawing information buffer 11 corresponding to yd. Therefore, the process of step S8 cannot be executed in yd. For this reason, the drawing data generation method of the first embodiment cannot completely generate the drawing data of the arc B.

  On the other hand, the drawing coordinate generation program 13B calculates the x coordinate of all the pixels included in the straight line C for each yi, and registers this x coordinate in the corresponding horizontal line drawing information buffer 11, that is, This includes the process of step S13 described later. As a result of this processing, the horizontal line drawing information buffer 11 corresponding to yd registers a pixel 25 and a set of pixels located on the outermost side of the first arc 23. For this reason, the CPU 2 can execute processing of step S20 described later controlled by the pixel drawing program 14B. This will be specifically described below.

  First, the CPU 2 sets the line thickness n specified in the space specified by the x coordinate axis and the y coordinate axis exemplified in FIG. 6 and the center point, radius r, specified as a graphic parameter, not shown. Based on the central angle α and the like, the upper end ya and the lower end yb of the y-coordinate constituting the first arc 23 are calculated (S11). The first arc 23 is different from the first circle 21 described above in that the central angle α is, for example, 90 degrees and has end points 23a and 23b, but the radius is the value of the first radius. It is the same. Next, the CPU 2 secures the horizontal line drawing information buffer 11 corresponding to each horizontal line from the upper end ya to the lower end yb (S12).

  Then, as described above, the CPU 2 calculates the x coordinate of the pixels constituting the straight lines C and D connecting the end points 23a and 23b of the first arc 23 and the end points 24a and 24b of the second arc 24, It is registered in the horizontal line drawing information buffer 11 (S13). That is, in step S13, for the straight line C, each of the pixel including the end point 23a, the pixel 25, and the pixel including the end point 24a is stored in the coordinate data storage unit 16 of the horizontal line drawing information buffer 11 corresponding to ya, yd, and ye. The x coordinate of is registered. For the straight line D, the x-coordinates of the pixel including the end point 23b, the pixel 26, and the pixel including the end point 24b are registered in the coordinate data storage units 16, 17, and 18 of the horizontal line drawing information buffer 11 corresponding to yb. Is done.

  Next, the CPU 2 registers the number of registered x coordinates in the registered score storage unit 15 of the corresponding horizontal line drawing information buffer 11 (S14). Here, “1” is registered in the registration point storage unit 15 of the horizontal line drawing information buffer 11 corresponding to ya, yd, and ye, respectively. Furthermore, “3” is registered in the registration point storage unit 15 of the horizontal line drawing information buffer 11 corresponding to yb. Then, the CPU 2 registers the x-coordinate of the outermost pixel among the pixels constituting the first arc 23 in yi in the horizontal line drawing information buffer 11 (S15), and registers the registered number as the registration score. Register in the storage unit 15 (S16). For example, if the y coordinate is yc, x4 is stored in the coordinate data storage unit 16 of the horizontal line drawing information buffer 11 corresponding to yc, and “1” is registered in the registration point storage unit 15.

  Next, the CPU 2 registers the x coordinate of the innermost pixel among the pixels constituting the second arc 24 at yi in the horizontal line drawing information buffer 11 (S17), and registers the number of registrations. It is registered in the score storage unit 15 (S18). For example, in the case of yc, x3 is stored in the coordinate data storage unit 17 of the horizontal line drawing information buffer 11 corresponding to yc, and “2” is registered in the registration point storage unit 15. Further, the CPU 2 rearranges the x coordinates registered in the horizontal line drawing information buffer 11 corresponding to the y coordinate in ascending order (S19).

  Then, the CPU 2 executes the pixel drawing program 14B, refers to the rearranged x coordinates two by one, makes one set, one x coordinate included in the one set as a start point, and the other x coordinate as an end point. Then, based on the data of the coordinate points from the start point to the end point, drawing data is generated and a horizontal line is drawn while performing a mixing process for each coordinate point (S20). For example, in yc, drawing data for each coordinate point from x3 to x4 is generated. In particular, in the horizontal line drawing information buffer 11 corresponding to yd, the x coordinate of the pixel 25 is registered at step S13, and the x of the pixel located at the outermost side among the pixels constituting the first arc 23 at step S15. Coordinates are registered. For this reason, according to step S20, CPU2 can produce | generate the drawing data for every coordinate point of the outline of the circular arc B in yd, and the pixel which comprises the inside. In short, when drawing a horizontal line at yd, a pixel drawn twice is not generated.

  Further, the CPU 2 increments yi by 1 (S21), and determines whether yi is the lower end yb (S22). If yi is not yb, the CPU 2 returns to step S15 again and repeats the processing up to step S22. In short, since a horizontal line is drawn in step S20 for all yi from the start point to the end point, a circle having a specified thickness n and radius r is generated without generating pixels to be drawn twice. Drawing data of arc B, which is a part, can be generated. Thus, the CPU 2 can display the expected drawing result on the liquid crystal display 7 by executing the drawing coordinate generation program 13B and the pixel drawing program 14B.

  As mentioned above, although the invention made by this inventor was concretely demonstrated based on embodiment, it cannot be overemphasized that this invention is not limited to it and can be variously changed in the range which does not deviate from the summary.

  For example, when generating the drawing data for the circle A or the arc B, the CPU 2 increments the y coordinate by one after executing steps S8 and S20, and then performs the above-described processes from the upper end to the lower end of the y coordinate. However, the present invention is not limited to this. That is, since the circle A and the arc B have symmetry, it is not always necessary to calculate from the upper end yA to the lower end yB of the y coordinate in the circle A, for example, and the remaining coordinates are calculated from the upper end yA to the y coordinate of the center point O. The coordinate points may be calculated using symmetry. In this way, it is not necessary to calculate the lower end yB in step S1, and the number of horizontal line drawing information buffers 11 secured in step S2 can be substantially halved. Further, the figure having the end points is not limited to the arc B, but may be a hyperbola, a higher order curve, or the like. Even in such a case, the data of the coordinate points of the pixels included in the straight line connecting the end points may be calculated and stored in the horizontal line drawing information buffer 11. As a result, the horizontal line drawing information buffer 11 is configured with the x coordinate of the pixels included in the straight line and the x coordinate of the outermost pixel among the pixels constituting the outer contour graphic, or the inner contour graphic, for example. The x-coordinate of the innermost pixel among the pixels to be registered is registered. Then, the CPU 2 can generate drawing data based on coordinate point data from one coordinate point to the other coordinate point included in the set, with the two registered x coordinates as one set. Further, the x coordinate axis and the y coordinate axis are appropriate coordinate axes for specifying a space in which a figure exists, and are not limited.

It is a flowchart which illustrates the drawing data generation method which concerns on Embodiment 1 of this invention. It is explanatory drawing which illustrates the data processor 1 which concerns on embodiment of this invention. It is explanatory drawing which illustrates schematic structure of a horizontal line drawing information buffer. It is explanatory drawing which illustrates the position of the pixel contained in the 1st circle and 2nd circle which comprise a circle. It is a flowchart which illustrates the drawing data generation method which concerns on Embodiment 2 of this invention. It is explanatory drawing which illustrates the position of the pixel contained in the 1st circular arc and 2nd circular arc which comprise an circular arc.

Explanation of symbols

1 Data processor 2 Central processing unit (CPU)
3 Liquid crystal display interface circuit (LCDIF)
6 Bus state controller (BSC)
7 Liquid crystal display (LCD)
DESCRIPTION OF SYMBOLS 9 External memory 10 Program storage part 11 Horizontal line drawing information buffer 12 Frame buffer 13A, 13B Drawing coordinate generation program 14A, 14B Pixel drawing program 15 Registration point storage part 16-19 Coordinate data storage part 21 1st circle 22 2nd Circle 23 First arc 24 Second arc 23a, 23b, 24a, 24b End point A Circle B Arc

Claims (5)

A drawing data generation method for generating drawing data of a graphic based on a line thickness and a graphic parameter specified on a space specified by a first coordinate axis and a second coordinate axis,
A first process for calculating a start point and an end point on the first coordinate axis of an area including an outer contour graphic and an inner contour graphic according to the thickness of the line;
A second coordinate point for calculating the second coordinate point on the second coordinate axis of each of the outer contour graphic and the inner contour graphic for each first coordinate point on the first coordinate axis from the start point to the end point; Processing,
Of the second coordinate points calculated for each of the first coordinate points, select the outermost outer coordinate point in the outer contour graphic and the innermost inner coordinate point in the inner contour graphic, A third process of rearranging the outer coordinate point and the inner coordinate point in order of increasing or decreasing;
Drawing data is generated on the basis of the coordinate point data from the outer coordinate point to the inner coordinate point included in the set, with the outer coordinate point and the inner coordinate point as one set in the rearranged order. And a fourth process for generating drawing data. Fifth processing for calculating a third coordinate point between a straight line connecting a first end point included in the outer contour graphic and a second end point included in the inner contour graphic when an end point exists in the graphic Further including
In the third process, when there is the third coordinate point having the first coordinate point common to the first coordinate point of the second coordinate point, the third coordinate point and the outer coordinate point or the inner coordinate point Sort in ascending or descending order,
The drawing data generation method according to claim 1, wherein in the fourth process, drawing data is generated based on data of coordinate points from the third coordinate point to the outer coordinate point or the inner coordinate point. When the figure is a circle, the figure parameters are center point and radius;
The outer contour graphic is a first circle centered on the center point and having a first radius larger than the radius,
The inner contour graphic is a second circle having a second radius that is centered on the center point, smaller than the radius, and whose difference from the first radius is the thickness. Drawing data generation method. When the radius is r and the thickness is n, if n is an odd number, the first radius is an integer part of a value represented by r + n / 2, and the second radius is r− the integer part of the value indicated by n / 2,
4. The drawing according to claim 3, wherein if n is an even number, the first radius is a value represented by r + n / 2-1 and the second radius is a value represented by rn / 2. Data generation method. A data processor having a central processing unit and a program memory for storing a program executed by the central processing unit,
The program memory has a drawing data generation program for generating drawing data of the graphic based on the line thickness and graphic parameters specified in the space specified by the first coordinate axis and the second coordinate axis,
The drawing data generation program includes: a first process for calculating a start point and an end point on the first coordinate axis of an area including an outer contour graphic and an inner contour graphic according to the thickness of the line;
A second coordinate point for calculating the second coordinate point on the second coordinate axis of each of the outer contour graphic and the inner contour graphic for each first coordinate point on the first coordinate axis from the start point to the end point; Processing,
Of the second coordinate points calculated for each of the first coordinate points, select the outermost outer coordinate point in the outer contour graphic and the innermost inner coordinate point in the inner contour graphic, A third process of rearranging the outer coordinate point and the inner coordinate point in order of increasing or decreasing;
Drawing data is generated on the basis of the coordinate point data from the outer coordinate point to the inner coordinate point included in the set, with the outer coordinate point and the inner coordinate point as one set in the rearranged order. A data processor for controlling the fourth process.

Images